How to Read a Light Bulb Label

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Even though CFLs have been around for a while, it can still be confusing and discouraging to stand in front of a store shelf with dozens of light bulbs to choose from. How do you know what you need? How do you know what you’re getting? Fortunately, most of the information you need is on the packaging label. New federal labeling requirements launched in 2012 help consumers make educated purchases when replacing inefficient incandescent bulbs.

Let’s break down the main parts of the label so you will feel more confident standing in that light bulb aisle.

Brightness: Most people equate watts with brightness – a 40 watt bulb is not very bright, but a 150 watt bulb is very bright. But watts really tell you how much energy the bulb is using. The number of lumens produced by a bulb is actually the figure that explains how bright a bulb burns. With new energy-saving light bulbs you can’t rely on watts to tell you how bright a bulb is. The higher the lumens, the brighter the bulb. This chart shows the average lumens for a traditional incandescent bulb:

150w = 2,600 lm

100w = 1,600 lm

75w = 1,100 lm

60w = 800 lm

40w = 450 lm

Estimated Yearly Energy Cost: This is pretty straightforward, but you should look at the values used to calculate the cost (3 hours a day and 11 cents per kWh) and change them for your circumstances to get an accurate number for you. Despite your specific values, this is a good comparison tool to see which light bulb at the same lumens costs the least to operate.

Life: Based on using a bulb for three hours a day, this number will give you the bulb’s life expectancy. Lifespan can be affected in many ways. For example, CFLs don’t perform as long when they are exposed to extreme temperatures, moisture or movement or if they are turned on and off repeatedly for short periods.

Light Appearance: The color of the light emitted by the bulb is listed in Kelvins. Incandescent bulbs give off a warm, soft light we are familiar with and fall in the 2,700-3,000K range. Bulbs of this color are best for relaxed settings, such as the family room or bedroom. The 3,500-4,100K range gives off a bright, cool white light best for the kitchen and office, and the 5,000-6,500K range gives off light that best imitates bluish daylight, which is good for reading or task lighting.

Energy Used: This number will be listed in watts – and the lower the number the less energy it uses. You may be used to buying 75 watt bulbs for your home, but now the average watt bulb you bring home may be closer to 20 watts!

If possible, look for a store where you can test various bulbs to see how bright and what color they are. Since some of the newer, most energy-efficient bulbs are rather expensive, and you want to make sure you know what you’re getting before you buy.